Do you know what a deadhead is? Or a squawk? Or how to respond to a pan-pan?

These are just a few examples of the special language that pilots must speak – whatever their nationality.

The language of flight, or Aviation English – which consists of around 300 words – is a combination of professional jargon and plain English.

It was created to avoid pilots and air controllers mishearing each other – to avoid potentially fatal accidents taking place.

One of the deadliest plane disasters in history was partly caused by language confusion.

In 1977, the Dutch captain on a flight to Tenerife told air traffic control: “We are at takeoff”.

Tragically, the Dutch and English words were confused and due to poor weather conditions, the control tower could not see two planes headed for collision.

At least 583 people were killed.

Following several such air traffic accidents, the International Civil Aviation Organization (ICAO) suggested that English should be the international language of aviation — and that pilots and air traffic controllers must have at least a basic knowledge of it.

International Phonetic Association

But it’s not English as we know it. According to the Oxford Dictionary blog: “Learning to speak on the aircraft radio is one of the most challenging aspects of learning to fly and new pilots must sit written and practical exams to prove their proficiency.”

To understand pilot speak, you must first learn the international phonetic alphabet.

Then comes a list of words you may have heard on flights such as “roger” – meaning understood, “affirm” – meaning yes and “approach” meaning coming in to land.

While the language of aviation is continually changing, pilots are required to pass strict language tests in order to fly planes safely.

Pilot speak…and what it means

Affirm: Contrary to popular belief, pilots do not say “affirmative” when they mean yes – the correct term is affirm, pronounced “AY-firm.”Approach: Coming into land.Deadhead: This refers to a member of the airline crew who is traveling in a passenger seat.Mayday: This is one you don’t want to hear. The distress call for life-threatening emergencies, such as complete engine failure. It comes from the French “m’aidez” (“help me.”) Pilots must stay it three times at the start of a radio call.MEL – Minimum Equipment List: This means a particular aircraft appliance is broken but is not needed for safe flight – such as the coffee maker.Pan-pan: The next level of emergency down from a Mayday; used for situations that are serious but not life-threatening. Originating from the French word ‘panne,’ meaning a breakdown. You say it three times: “pan-pan, pan-pan, pan-pan.”Roger: This means “message received,” but it doesn’t necessarily mean that you’ll comply.Squawk: To squawk is to set your transponder (a device for receiving a radio signal) so that your location can be identified on a radar. Pilots might be asked to “squawk Mode Charlie” or “squawk ident,” which are unique settings to help air traffic control to see where you are.Standby: This means “Please wait” and this is usually said when the air traffic controller or pilot is too busy to take a message.Wilco: An abbreviation of “will comply,” meaning received the message and will comply.